To the best of my knowledge or recollection of posts here in the LS forum, LSDarkShadow is the only one I'm aware of that did what you are trying to do. You may want to send him a PM to ask him about this. I think he had to order different speaker grills to work with the speakers he installed (Volfenhag).
He could also give you his opinion on the sound quality. Most of us that have put an aftermarket stereo in did NOT reconnect those speakers as they really weren't designed to be a main part of the car's soundstage. The reason for this is that those speakers will be firing directly opposite of the speakers that are in the door panels. When speakers are close together and are firing into each other, you run the risk of signal frequencies stepping on each other, and somewhat "muddying up" the sound that eventually reaches your ears (the soundstage). The 2.5" speakers that can from the factory were only there as "effect" speakers - to provide delay and such to make it seem like you were in a different environment (concert hall, church, etc). Since those speakers actually fire away from your ears, they're really not going to add to your soundstage, and actually may detract from it.
There are quite a few guys here in the LS forums that are pretty knowledgeable about car audio (I'm not one of them - yet). 1LoudLS is actually an audio installer, and can tell you straight what's going to happen in a particular audio install (he's got the experience to back it up).
So, good luck and hopefully it works out the way you want it to. That's all that matters in the end. I'd reach out to LSDarkShadow to get his help on what you're trying to do.
TRU - can you hear me now? (shoot, already broke my promise)
